The Merits of Inherent Shutdown vs Mechanical Shutdown of a Platetype, Water-Moderated and -Reflected Reactor in a Runaway Condition

Transient Tests of the BSR-Ii Core in the Spert I Facility

“…In the static technique for the measurement of &/peff by use of l/v absorbers, the perturbation 6Ca in absorption cross section, introduced by the addition to the reactor of a small quantity of l / v absorber such a s boron, is related through the lifetime to the resultant reactivity change in dollars R by Here, the volume integration is taken over the entire reactor, and for the jth neutron energy group, mfOj is the unperturbed adjoint flux, Qj the perturbed flux and, assuming a l / v dependence for boronover the entire neutron spectrum, uaj is given by ~~e c i i l i z a t i o n of Equation (5) to a Spert two-region (oore and water:.. reflector) reactor model yields where Nc and Nr, respectively the uniform boron concentrations in the core and water-reflector regions, a r e related through the volume fraction of water The determination of ,&/peff in Equation (4) thus involves the measurement of the reactivity change R when the entire reactor is poisoned and also the measurement of the weighting factor f (or equivalently, 1-f) through the reactivity change obtained when only the core (or reflector) is separately poisoned.…”